Bicycle chainring

Abstract

A bicycle chainring is formed from a first member and an second member. The first member includes a center rotational axis, a crank attachment portion with a plurality of chainring attachment openings and an annular tooth portion with a plurality of chain engaging gear teeth. The second member disposed around the center rotational axis and is fixedly attached to overlie at least one of the crank attachment portion and the annular tooth portion to reinforce the first member without obstructing access to the chainring attachment openings.

1. A bicycle chainring having a center rotational axis comprising:
 a first member having an annular shape; and 
 a second member having an annular shape, 
 at least one of the first member and the second member being formed with an annular tooth portion with a plurality of chain engaging gear teeth, 
 the first member including a crank attachment portion with a plurality of chainring attachment openings, and the second member including an inner peripheral portion with a plurality of chainring attachment openings, 
 the first and second members being fixedly attached to overlie each other without obstructing access to the chainring attachment openings of the first and second members, and 
 the inner peripheral portion overlying the crank attachment portion of the first member and being formed with an axially extending wall that is disposed axially between the first and second members with respect to the center rotational axis and that extends toward the first member in an axial direction along the center rotational axis, the axially extending wall including at least first and second wall portions located at each of the chainring attachment openings of the second member, the at least first and second wall portions extending along an inner edge of the inner peripheral portion with a hollow interior area being at least partially formed axially between axially spaced faces of the first and second members and between the at least first and second wall portions of the axially extending wall. 
 
   
   
     2. The bicycle chainring as set forth in  claim 1 , wherein
 the first member and the second member are fixedly coupled together at the annular tooth portion of the first member. 
 
   
   
     3. The bicycle chainring as set forth in  claim 1 , wherein
 the first member and the second member are fixedly coupled together at the crank attachment portion of the first member. 
 
   
   
     4. The bicycle chainring as set forth in  claim 3 , wherein
 the first member and the second member are fixedly coupled together at the annular tooth portion of the first member. 
 
   
   
     5. The bicycle chainring as set forth in  claim 2 , wherein
 the first member and the second member are fixedly coupled together by a plurality of rivets. 
 
   
   
     6. The bicycle chainring as set forth in  claim 2 , wherein
 the first member and the second member are fixedly coupled together by welding. 
 
   
   
     7. The bicycle chainring as set forth in  claim 2 , wherein
 the first member and the second member are fixedly coupled to together by an adhesive material. 
 
   
   
     8. The bicycle chainring as set forth in  claim 3 , wherein
 the first member and the second member are fixedly coupled together by a plurality of tubular fastening members with one of the tubular members being axially aligned with each of the chainring attachment openings. 
 
   
   
     9. The bicycle chainring as set forth in  claim 8 , wherein
 each of the tubular fastening members includes a first fastening member and a second fastening member. 
 
   
   
     10. The bicycle chainring as set forth in  claim 9 , wherein
 the first and second fastening members of each of the tubular fastening members are concentrically arranged. 
 
   
   
     11. The bicycle chainring as set forth in  claim 9 , wherein
 each of the first fastening members includes a first tubular section and a pair of oppositely facing abutment surfaces that abut against interior axially facing surfaces of the second member and the first member, and 
 each of the second fastening members includes a second tubular section and an abutment element extending radially from the second tubular section to abut against an exterior axially facing surface of one of the second member and the first member. 
 
   
   
     12. The bicycle chainring as set forth in  claim 1 , wherein
 the second member includes an outer peripheral portion overlying an inner part of the annular tooth portion of the first member at a location that is disposed radially inward of the chain engaging gear teeth. 
 
   
   
     13. The bicycle chainring as set forth in  claim 12 , wherein
 the chainring attachment openings of the second member are axially aligned with the chainring attachment openings of the first member. 
 
   
   
     14. The bicycle chainring as set forth in  claim 13 , wherein
 the first member and the second member are fixedly coupled to together by a plurality of tubular fastening members with one of the tubular members being axially aligned with a respective pair of the chainring attachment openings of the first and second members. 
 
   
   
     15. The bicycle chainring as set forth in  claim 14 , wherein
 each of the tubular fastening members includes a first fastening member and a second fastening member that are nested together. 
 
   
   
     16. The bicycle chainring as set forth in  claim 14 , wherein
 each of the chainring attachment openings of the second member has an outer diameter that is larger than an outer diameter of each of the chainring attachment openings of the first member. 
 
   
   
     17. The bicycle chainring as set forth in  claim 1 , further comprising
 a non-metallic filler material at least partially disposed in the hollow interior area. 
 
   
   
     18. The bicycle chainring as set forth in  claim 17 , wherein
 the filler material is a resilient material. 
 
   
   
     19. The bicycle chainring as set forth in  claim 1 , wherein
 the second member is made from a first material that is softer than a second material of the first member. 
 
   
   
     20. The bicycle chainring as set forth in  claim 1 , wherein
 the crank attachment portion of the first member includes an outer annular part with a plurality of radially inward extending parts that include the chainring attachment openings of the first member. 
 
   
   
     21. The bicycle chainring as set forth in  claim 20 , wherein
 the inner peripheral portion of the second member includes a plurality of radially inward extending parts and the second member further includes an outer peripheral portion, 
 the radially inward extending parts of the first member and the second member overlying each other, and 
 the outer peripheral portion of the second member overlying the outer annular part of the crank attachment portion of the first member. 
 
   
   
     22. The bicycle chainring as set forth in  claim 21 , wherein
 the chainring attachment openings of the second member are axially aligned with the chainring attachment openings of the first member. 
 
   
   
     23. The bicycle chainring as set forth in  claim 22 , wherein
 the first member and the second member are fixedly coupled to together by a plurality of tubular fastening members with one of the tubular members being axially aligned with a respective pair of the chainring attachment openings of the first and second members. 
 
   
   
     24. The bicycle chainring as set forth in  claim 1 , wherein
 the first member and the second member are concentrically and fixedly coupled together about the center rotational axis.